It's Only Rocket Science! (RSS/RO/RP-1)

[jimmymcgoochie]

What use is a huge new launch rocket if it doesn't have anything to launch? Enter Purple Circle, mostly built out of existing stages stacked on top of each other stacked on top of a 1500-ton rocket, throwing about 25km/s of delta-V at the question 'how do you get to Mercury orbit without a complicated series of gravity assists?' in the hopes that the answer is 'about 25km/s of delta-V'.

It also turns out that the ideal parking orbit for a Mercury transfer is nowhere near the plane of the Moon's orbit and that launching correctly can knock 2km/s off the transfer burn.

Green Lime, take two. Now with the revolutionary feature of 'actual power generation' so this "power module" can power itself long enough to get to the station.

The station was spinning uncontrollably when Green Lime 2 arrived, but at some point between completing the rendezvous and approaching to dock, the station stopped spinning. I don't know why as the persistent rotation part of RO should have kept it tumbling, but it made docking so much easier.

Docking took place in the dark. As is right and proper. And the power module contract was comple- wait...

Eh? How did that happen?

With one contract completed (and another fake-completed), the new propulsion system was given a brief test to recircularise the orbit.

The crew, Klaus and Vera again, were next to launch.

Once the crew were back aboard I discovered a bit of weirdness with the science module- it has all the Kerbalism-related science stuff in it (crew science, lab, data storage) but also has a stock-style lab and experiment too which can generate 30 science per biome and be processed in the stock lab for even more science. KSP apparently didn't like the idea of me cheesing that for massive science income though and crashed when I ran it a few times, then disintegrated after reloading the save, so I decided to leave it be and went back to a slightly earlier save.

With that out of the way, it's time to look back to Mars as the Blue Guitar missions arrive. Both suffered an unexpectedly high rate of hydrogen boiloff leading to excess lox in the tanks, but by dumping that excess both probes ended up with more than enough fuel to capture into orbit and throw their respective probes at their respective moons.

Blue Guitar 2 was first to arrive:

Decoupling this probe accidentally bumped the main probe's orbital period from 19 to 56 days due to the high eccentricity, however this allowed a cheap transfer to Deimos for the little probe and a cheap plane change to near-polar orbit for the big one to do some scanning.

Blue Guitar 1 arrived about two days later:

The post-capture trajectory had a coincidental close approach with Phobos, so the moon probe was quickly decoupled and threw itself at Mars' inner moon. Contracts were completed along the way as its trajectory changed:

And the first sight of a Martian eclipse came during the capture burn at Phobos:

That big fuel reserve came in handy- the probe made it to polar Phobos orbit with a comfortable reserve and will be more than capable of landing on Phobos on just RCS thrust; no biome hopping though, since neither Phobos nor Deimos have biomes any more, just 'surface'.

With those Martian missions working out well, I went back to the Green Kiwi rovers that had failed so spectacularly and installed a proper re-entry capsule with a heatshield to withstand an atmospheric entry from a hyperbolic trajectory. The rover's offset centre of mass resulted in a lifting re-entry, though the first test didn't have any RCS thrusters so couldn't make the most of it.

This test had a poorly configured parachute, which snapped and sent the rover crashing into the surface at supersonic speeds.

A few upgrades later (most notably a better parachute and some RCS thrusters to point the re-entry capsule in the right direction) and it was all going fine- until I fat-fingered the spacebar and deployed the aeroshell at somewhere around Mars orbital velocity.

Rather surprisingly this did zero damage and a safe landing still ensued:

The design seems solid and simulations using the booster from the Green Banana Saturn gave it enough delta-V to get to Mars with a decent margin for slowing down. Green Kiwis 3 and 4 are now on the build queue, but the next Mars window is a while away yet.

Spoiler

Full album: https://imgur.com/a/EeKb5Fl

Coming soon: MOAR ASTRONAUTS! Two pairs just isn't going to be enough for future missions and they'll take a while to train up on Gemini, which will then cover for the first four to retrain with something newer like Apollo or the D-2.

[jimmymcgoochie]

New astronauts!

They'll take almost a year to get trained up for the Gemini capsule before they can do any missions, which should allow the four existing astronauts to retrain on something new like the Apollo or D-2 capsules. Gemini is OK, but the limited delta-V in the service module is a pretty big limiting factor.

With a capable 1500-ton launch rocket now available, why launch a lunar lander and lunar Gemini separately when they can go together?

These tests ran into a few problems:

In order for the Gemini capsule to return, it needs that upper stage, but there's no way for it to reattach to the upper stage once the lander is gone. Cue a dubious retrofit to add docking ports on the front of the upper stage and the bottom of the Gemini service module.

A quick abort test...

...and Yellow Marimba is good to go. Lunar orbit and landing contracts are waiting.

Meanwhile, over at Mars:

Blue Guitar 2's primary prober completes a successful orbital capture at Deimos with a mildly ridiculous amount of fuel left over thanks to the efficient transfer. Orbital velocity is 3m/s here. Three.

Blue Guitar 2 itself came back down to its periapsis a few days later and used up its remaining fuel to try and circularise. Background boiloff has cost it a considerable amount of delta-V even with MLI and radiators to keep that hydrogen cold, but there's just enough to reach a low and nearly circular orbit.

The relatively low inclination won't cover much of the planet for scanning purposes, but it's enough to get things started. Now out of fuel, the only way to try and adjust the slightly lopsided orbit was to decouple the landers, but due to some possible part clipping issues this resulted in both the lander and the main craft spinning wildly as the lander hurtled away at considerable speed.

The first lander performed a deorbit burn in the dark to land on the daylit side, dropping short of Olympus Mons to try and get some atmosphere for the parachutes to use.

The probe landed at a relatively gentle 6m/s and- bounced, flipped and tumbled downhill, breaking one of the solar panels in the process. It also ended up underneath the rendered terrain, but still on top of the 'real' terrain.

Three solar panels are enough to power everything even with the science experiments running and data transmitting, though the latter depends on Blue Guitar 2 being overhead as the probe only has a small transmitter and the only other probe currently in orbit, Green Banana Mars, has no way of connecting to the lander.

With one successful Mars landing done, the second lander was decoupled and sent on its way. Unfortunately, the decoupling force was enough to drop its periapsis below the surface and on the night side to boot. The rate of descent was too fast to allow sufficient aerobraking, the parachute deployed but broke from the strain and the lander hit the ground at over 600m/s.

That contract money was enough to pay for a tracking station upgrade, which I think installs the X-band receivers? Either way, better signals back to Earth are always good.

And finally, another geostationary contract sat launch netted some additional funds.

Spoiler

Full album: https://imgur.com/a/DysSxdc

Coming soon: I'll be away for a while, but when I return there's a second Mars mission with two more landers to try and land, transfer windows to Mercury, Jupiter and Ceres in quick succession and a lunar base and station to design.

[jimmymcgoochie]

Two months in space bags a significant milestone payout, but also causes worrying stress levels for Klaus and Vera.

Probably best to bring them home again before one of them tries to open a window to let the smell out.

The funds from the 60-day milestone went into KCT points, added to both VAB and R&D.

With that out of the way, it's back to Mars. The Blue Guitar missions have been highly successful so far: the moon probes dispatched to Phobos and Deimos, two landers sent to the surface (but only one of them actually landed intact) and one of the orbiters in its final orbit for science, scanning and signal relaying. Blue Guitar 1 still has its landers on board, so it's time to send those down to the surface.

A flawless landing and no damaged solar panels. Maybe the other one can-

The final braking burn was slightly too late and the engine was destroyed on impact, then the probe bounced a few metres into the air and broke a solar panel when it landed the second time. Still, three successes out of four is pretty good going considering how crude these landers are.

Blue Guitar 1 wasn't finished though, with one final burn parking it in a low polar orbit from where it could scan the whole surface of the planet.

A contract came up to do a four satellite geostationary network. Doesn't say they have to be in any kind of pattern, just four satellites in geostationary orbits with 315 payload each, so I can launch all four in one go.

A small science core with a service module tank wrapped around it ticked all the boxes, with a lightly modified Green Cucumber GEO rocket more than capable of putting them into geostationary orbit and then deorbiting the upper stage afterwards.

A few days later, Blue Sitar 1 arrives at Venus. The boil-off issues suffered by the nearly identical Blue Guitar missions didn't happen on this one, even though it went closer to the Sun instead of away from it, so there was plenty of fuel to capture into a circular polar orbit for science, scanning and deploying the quartet of landers.

A valuable contract completed, plus a bonus that appeared during the approach to Venus:

Deploying the landers turned out to be rather problematic- a combination of decoupler force and possibly some minor part clipping means that the landers get hurled off and sent tumbling when the decouplers fire, which their tiny RCS thrusters can eventually cancel out. Firing the deorbit motors usually causes them to spin again, then decoupling the retro stage focusses on that stage and not the lander and decoupling the heatshield is a BIG no-no and is just plain Kraken bait.

Oh, and the parachutes seem to be configured for Mars, not Venus, with a diameter of 50m when 50cm would probably be overkill.

But despite all that, the first lander managed to plonk itself down on the surface with only one solar panel broken on impact (not sure how, they should have been protected by the heatshield) and has begun to run its experiments. Solar power is all but useless on the surface so once the batteries are flat they're dead for good.

The second lander didn't fare so well: deploying the parachute early to prevent it from being destroyed by aero forces worked, but decoupling the heatshield caused several explosions and a massive Kraken attack that sent the whole thing spinning wildly.

Atmospheric drag stopped the spin eventually, but running at 10x physics warp eventually came back to bite me as first the parachute and then the whole probe were obliterated by ludicrous overpressure that in some cases went into the gigaPascals.

Still, two more landers left to try and get some additional science plus I discovered that there are three other probes orbiting Venus that can act as relays, increasing the signal coverage considerably.

Spoiler

Full album: https://imgur.com/a/UAcV2D5

Coming soon: Transfer windows to Mercury and Jupiter, plus a new set of science experiments that will be researched at almost exactly the same time as the Jupiter window. I have two Jupiter-bound probes to launch, so one will be refitted while the other launches on time.

[jimmymcgoochie]

After a long journey away from the Sun, Blue Mandolin Vesta finally arrives at its destination.

Much braking later, it had an apoapsis (good) but the periapsis was negative (bad) so a course correction is needed.

But while that probe floated slowly towards its next burn, Purple Circle 1 was ready to launch in an attempt to orbit Mercury. I think this is the first 1500 ton rocket launch in this career.

Despite making it to orbit with this much rocket left, it's pretty unlikely that it'll actually make orbit of Mercury due to the huge delta-V requirements.

And smash cut back to Vesta where the orbit was established and the contract was completed. There's even some fuel left to try and land, though that'll wait until after the orbital science has been done as there's probably not enough to get back to orbit after landing.

Mercury isn't the only transfer window available though- there's also one for Jupiter and two probes queued up to launch. With a new science node unlocking just a few days before the ideal launch window, the second probe was refitted with better science while the first launched as-is.

Unfortunately, at this point I did some mod updates and something broke Minimum Ambient Lighting completely. If you don't know what that does...

The issue persisted with the next launch, a geostationary contract sat:

Although that wasn't the only issue that that mission ran into:

The usually reliable RD-58 failed to ignite for the circularisation burn. So much for superior Soviet staged combustion...

To get over that disappointment, I went over to Venus to land Blue Sitar 1's two remaining landers. Much like the first two, the Kraken was lying in wait in the Venusian atmosphere.

Most of the external parts- solar panels, RCS, parachute, experiments- were lost, but the impact was still survivable and the experiments inside the probe core itself kept working, as did the surface scoop. No more jettisoning the heatshield though, it's a recipe for disintegration.

The fourth lander, for some reason I can't quite figure out, had the correct parachute configuration for Venus rather than for Mars. Yet it still managed to land upside down and only flipped over after I decided jettisoning the heatshield to flip it right side up was worth the risk.

Once again the solar panels didn't survive, but they generate almost zero power anyway so it didn't matter too much. The onboard batteries lasted for about five days, enough time to gather some useful data and transmit it to one of four orbiting probes to relay it back to Earth.

Now a quick crewed mission for some dubious contract cheesing- sending a Gemini with two crew aboard up to the Yellow Timpani space station will complete two contracts, one for sending a new crew and one for adding a power module; since the station already generates enough power for the contract, just docking anything to it will do.

Another mod update messed up the docking port, making it not decouple the nosecone when it was staged. This definitely worked before, but weirdly when I sent Patrick out to do some EVA construction on it, the nosecone popped right off by itself.

Within a day they were closing in on the station:

Once docked, they shuffled some supplies around, dropping off some of their food, water, liquid oxygen and lithium hydroxide in exchange for a bit of extra RCS propellant for the upper stage.

Having made this mission at least nominally legitimate, the crew bumped their apoapsis up a bit to start their orbital flight with 2 crew contract, but also to get a good view of Blue Mandolin Jupiter 2 as it launched.

Rolling back mod updates fixed the darkness issue:

And the probe is away, carrying with it a selection of upgraded science experiments including that new magnetometer boom.

Spoiler

Full album: https://imgur.com/a/A30mjM3

Coming soon: Crewed lunar contracts are ticking down and there's a new 1500-ton single launch Moon landing system to try out. I also need to start working on a Moon base and station.

[jimmymcgoochie]

Mini update today:

Klaus and Vera came back down from low Earth orbit to complete the third of three contracts, bringing in over half a million funds in total.

Then I spent a while looking at planes. There's a whole series of X-planes supersonic contracts just sitting there and no obvious reason not to do them, so I dusted off the old AR-3 rocketplane designs, stuck a jet engine on the back instead of rockets and tweaked the wings a little bit to match the new rear end. The results were promising:

800m/s and it was still accelerating, though I doubt the engine could push it much faster without overheating. Better jets will unlock in future nodes including a ramjet that should be very effective at high speeds, though produce no thrust at low speeds; with an airdrop of over 1100m/s available now that won't be an issue.

During testing, there were a few issues with important bits breaking off due to high-speed, low altitude, high-gee manoeuvring...

Spoiler

Not all of them survivable...

Full album: https://imgur.com/a/r3mZ3av

Coming soon: Designing some lunar infrastructure, eventually...

[jimmymcgoochie]

Plans for lunar infrastructure are advancing slowly, with designs for a lunar base and a lunar station going through testing.

The base needs more work, but the station is ready to go and has been named Yellow Carillon. The station science module on the top has four crew experiments to run in lunar orbit, with more experiments available if I can send extra modules up with visiting crews.

Meanwhile, with no crew available to actually fly the new SJ-1 high-speed jet, I took a look at a potential upgrade with a newly unlocked engine (nicked from the SR-71 Blackbird). I also switched to an uncrewed design before realising that the X-planes supersonic contracts require at least one crew on board.

With a maximum speed of well over 1100m/s before the nose started melting from the heat, a maximum altitude of 40km reached in a power climb and reasonable low-speed performance (after a weight distribution issue was resolved so it didn't backflip right off the runway on takeoff), there's clearly a lot of scope for boosting the top speed of this plane. There's also a ramjet engine available which could be worth a look, but that would restrict the plane to solely air-dropped flights as it can't function at all at low speeds. Crew training for the X-15 cockpit will begin as soon as crew are free, so expect some fast jet action in 1968.

...wait, it's 1968?

Not the worst way to start the year with a contract completed by the Venus missions. Much of that money was spent unlocking tech level 7 communications which includes X-band frequencies that have much higher transmission rates and ranges than S-band.

Those new X-band systems were immediately put to use to design a set of high-powered relays for Earth orbit to support a future set of ultra-resolution imaging satellites. Yes, the "10,000 science over 20 years at 40kB/s" one. The Green Cucumber GEO satellite launcher provided a useful platform for sending these relays to a high Earth orbit with delta-V to spare.

The Green Nectarine is now on the build queue ahead of the first of four planned Green Mango imaging satellites, also launching on a Green Cucumber derivative.

Meanwhile, yet another Green Cucumber derivative, the Green Cucumber OrbSci, was launched into a fairly high (50Mm) polar orbit of Earth with a set of newly unlocked experiments to run in space high.

Science should be coming back from this probe for some time to come.

Spoiler

Full album: https://imgur.com/a/iCet5nS

Coming soon: A two-week hiatus as I will be AFK (away from Kerbal). X-planes flights and crewed lunar missions are on the cards when I return.

[jimmymcgoochie]

Moon landings so far have required two launches a couple of weeks apart and a lunar orbit rendezvous, but not any more.

Yellow Marimba is a single launch system that uses the same lunar Gemini and lunar lander as previous landings, only launched on the same rocket.

While that mission was en route to the Moon, Blue Mandolin Ceres' launch window opened.

It was all going according to plan, until...

That stage still had several km/s left in it and was required for the braking burn to capture into Ceres orbit. Looks like this is a flyby mission then.

Back to the Moon as Yellow Marimba 1 captures into orbit.

Notice that the lander is between the Gemini capsule and the upper stage, which is a problem as the upper stage is required to send the capsule back to Earth. Some docking shenanigans are required to extract the lander and reattach the capsule, not helped by the fact that I forgot to add batteries to the booster so it's completely uncontrollable unless docked to something else.

A little bit of shimmying around later and Klaus completes the docking while Vera prepares the lander for her descent. Klaus did the last landing, so now it's Vera's turn.

The targeted landing contract wants a landing site in the highlands. Good news, there's a big stretch of highlands right under their orbit; bad news, it's on the far side and also pretty rough terrain.

But a few craters weren't going to stop Vera getting her long-awaited Moon landing!

(Look at that Parallax terrain scatter... And that's not even Parallax 2.0, though people are working on configuring that for RSS.)

Once the science was done it was time to head back to orbit to complete a crewed lunar orbit contract, which requires two crew.

Unlike previous landings, this time I decided to put the lander to use afterwards by sending it into a high-inclination orbit to use its TV camera as a biome scanner; after pilfering all the useful supplies for the crew, of course. The solar panels are more than adequate to keep it running and there's a decent reserve of fuel to shift its inclination.

Once the contract was done, it was home time.

A highly successful mission all around- lots of contract money, lots of science and big delays to Klaus and Vera's retirement dates.

Re-accepting the crewed lunar orbit contract and spending some KCT points later:

Spoiler

Full album: https://imgur.com/a/Lh0focS

Coming soon: Rearranging the research queue to avoid speed penalties for researching stuff too soon, accepting contracts I probably shouldn't have accepted, and maybe I'll actually fly the plane this time?

 

[jimmymcgoochie]

Forgot to post and now I'm a whole imgur album behind and I've forgotten everything! What did I do-?

checks screenshots

Oh.

 

 

That.

If you've read my last RP-1 career report, you'll know I have a habit of accepting hugely valuable contracts before I have the tech nodes unlocked to actually complete them. Well, this time I've outdone myself:

In my defence, it gives me TWENTY YEARS to fulfil this contract as opposed to the ten years for the flyby and orbit contracts for Mars (and Venus) which should be more than enough time to get it done, plus 5.4 million funds up front. Put that together with the funds I already have and it's enough to buy a brand new launchpad with no weight or size limits, several hundred KCT points and pay for the entire fleet of orbital imaging satellites and the relays needed to stream their data back down to the DSN, among other things.

After a bit of thinking, I've come to the conclusion that I'm doing this "crewed Moon rover" thing all wrong- why bother with a self-controlled rover when you can literally strap four wheels and a chair to a plank and call it a day?

Despite how comical this thing looks, it actually works. With RCS for attitude control and solar panels to give it a modicum of power generation, it's capable of carrying one Kerbal around without too many issues. Besides the top-heavy centre of gravity, of course, but that's where the RCS comes in.

A test sim with the baby rover strapped to the side of a crewed Moon lander went mostly according to plan, showing that it wouldn't adversely affect the lander's ability to complete a landing and return to orbit.

Probably.

But it doesn't like going fast, and especially doesn't like slowing down again. Having about a centimetre of ground clearance will do that.

With that design now ready for a proper test, Yellow Marimba 2 is on the build queue to complete numerous contracts. It'll also be the first crewed vessel launched with the newly researched vacuum scrubbers, forever removing the need to carry around lithium hydroxide. One less thing to add to each crewed mission is always good.

And then an alarm popped up for Green Banana Mercury, the first flyby probe to visit the innermost planet. Why?

Turns out past me had set up a burn that would enable a second Mercury flyby, which will take place about a day after Purple Circle 1 Mercury arrives to try and orbit, or more likely do a really slow flyby as the delta-V required to capture is about 300m/s more than the probe has left.

Moving on to the first launch of this update, Green Nectarine is a set of four high-bandwidth relays launching to high Earth orbit to give the upcoming Green Mango orbital imaging satellites the data transfer speeds they need to operate properly.

Uh, MechJeb? Why are you pitching over so steeply? 30 degrees pitch at under 20km is not a good idea!

(It turned out that the PVG settings got reset by a MechJeb update and the pitch rate was set to 1 degree per second instead of the 0.7 I usually use; one revert later and it worked fine.)

The relays were launched to a very high (150Mm) apoapsis at a high inclination, then boosted into a 3/4 resonant orbit so the relays could be evenly spaced to improve coverage.

Each relay will do a circularisation burn every five and a bit days and I'll sync their orbital periods as closely as possible so that they don't drift.

Final scores:

Spoiler

Full album: https://imgur.com/a/0MysK3I

And despite what some people on the RP-1 Discord said, Apollo and D-2 docking ports ARE compatible with each other! That could be very useful for future space station designs.

Coming soon: Double Mercury encounters and playing around with some of the many parts I spent several million funds unlocking just because I could...

[jimmymcgoochie]

Before I get too far behind, here's post number fifty!

Each of the Green Nectarine relays executed its circularisation burn without any trouble and only using a small fraction of its fuel; turns out they were pretty overbuilt for this, but better safe than sorry.

With their orbital periods all synchronised to one thousandth of a second per orbit, they won't be moving out of formation any time soon. I haven't set up their four S-band dishes to point at anything yet, mostly because I can't remember if they're supposed to point at each other or the Green Mango imaging satellites and I haven't actually launched any Green Mangos yet.

Speaking of which:

A successful launch, the satellite reached its target orbit and deployed all its science equipment while the dishes were targeted at the four Green Nectarine relays.

Onwards to Mercury and the Purple Circle Mercury 1 probe which is going to try and capture into orbit. MechJeb says it's about 300m/s short of capturing into orbit and there's not much I can do to change that-

...or is there?

See, each of those stages has an RCS system on it, which means it has propellants that are dead weight to the stage's delta-V, unless I set the RCS to fire prograde with the main throttle and get some useful extra thrust while reducing the "dry" mass of each stage. 

After almost TWENTY MINUTES of braking burns...

And using up so much of the probe's fuel that the generic thrusters hit their residual limits and left just two 45N RCS thrusters to do all the work...

And having to dig the periapsis out of the ground because the braking burn was so long...

MERCURY ORBIT ON THE FIRST TRY!!! With almost nothing left in the tank, Purple Circle 1 manages the impossible and captures into Mercury orbit. It's not a great orbit, very eccentric and only just staying inside its SOI, but an orbit is an orbit and the contract completes while the science rolls in.

And in a total coincidence, less than a day after Purple Circle 1's arrival at Mercury, Green Banana Mercury shows up for its second flyby.

It gathers very little data on its way past, but just doing a double flyby when it was only ever designed for one is still pretty good going.

With that done, the final scores are in:

Spoiler

Full album: https://imgur.com/a/4U6LRk8

Coming soon: A lot of simulations as I experiment with launch vehicles, and the first real flight of my "new" supersonic jet.

[jimmymcgoochie]

I've been testing some new heavy launch rockets. First up is a variation on the Purple Shape using NK-15s instead of RD-253s; their greater ISP and lower fuel mass means the rocket is significantly lighter and the TWR off the pad is a bit higher, but the lower fuel density also means delta-V is marginally down and costs are slightly up due to the engines costing about 100 funds more each and using slightly stretched tanks to make the most of the greater mass budget.

Trimming almost 100 tons off the launch mass means there's a bit of scope for adding boosters, whereas the RD-253 version can only just squeeze 75 tons of payload inside the 1500 ton weight limit. The NK-15's biggest flaw is its relatively poor reliability, but when you're using 15 engines per rocket that'll go up pretty fast.

On to the first flight of the SJ-3 to rack up a (very) long overdue X-planes supersonic contract. It was only after the flight was over that I realised the separation motors on the cockpit ejection system meant it wasn't "jet engines only" but I'd rather cheat-complete the contracts afterwards than sacrifice that important safety feature.

Landing was a bit dodgy as the plane started drifting to one side, dropped a wing and then exploded despite the wingtip wheels that were added to prevent exactly that. Some design tweaks may be required before future flights, but with bigger and better engines waiting to be used this plane should be flying for a while yet.

Then I turned my hand to making a rocket that can lift 150 tons to LEO but without having to tool any new parts (besides the avionics), with a somewhat unconventional design:

Six F-1 boosters light on the pad to lift the rocket skywards. I took waaaay too many screenshots of the F-1s starting up as they shoot flames upwards before spooling up to full thrust; not sure I like the almost completely black effects though, they should be a lot more orangey-brown than that.

Once the boosters burn out, the core stage ignites its trio of RD-254s (vacuum-optimised RD-253s) and another trio of RD-02somethingorothers from one of the Proton upper stages; seriously, Soviet rocket engineers, you need a better system for naming your engines...  They're the ones without gimbals if that helps? There aren't a whole lot of vacuum-optimised large engines this far along the tech tree (I've just unlocked the 1969 engine nodes which includes the NK-15) so this was the best option available.

And finally, the upper stage of 2x RL-200 finished the orbital insertion. Unlike previous rockets that have used similar RL-200 stages, this one had an extra 5m tank on it to give it the required delta-V with the heavier payload.

Unfortunately, it couldn't even make it to orbit with a 135 ton ballast payload, so I tried asparagus staging the boosters and discovered that the first set of boosters separated at max-Q and promptly disintegrated (but no harm done to the rocket!).

But that didn't work either, so I pushed right up to the 3000 ton limit I'd set for this rocket and stuck some ugly blister tanks onto the boosters.

And it worked!

140 tons to LEO with this design by pushing the toolings and the launch mass to their absolute limits. While this isn't quite the 5% payload fraction I was after, it's pretty cheap in terms of tooling costs as only the avionics and that 5x5m tank need tooled. Unlike previous launch rockets which have managed orbit with just over 9km/s of delta-V on the pad, this one required an extra ~400m/s for some reason, which makes me think I can do better if I just build a really big rocket and pay the commensurately really big tooling costs that would ensue.

Spoiler

Full album: https://imgur.com/a/Q976gAA

Coming soon: 3 kiloton rocket, take two.

[jimmymcgoochie]

This "only use pre-tooled parts" thing isn't working out. How will a larger rocket fare?

Broadly similar in terms of engines to the previous design, this one uses a first stage core of 3x F-1 with a further three F-1s on boosters, then a 4x RD-254 second stage and then the same third stage as before. First and second stage tanks are 7.5m diameter and 10m long (the first stage uses three of them) because tooling one tank that size is expensive enough without tooling one thrice the length too.

The design showed some promise, when it wasn't destroying the third stage tanks due to MLI incineration by pitching a little too early, but ultimately didn't make it to orbit. It may have worked with the same payload as before, but I went back to 150 tons to see if I could do it.

Can I use a better engine anywhere? It's hard to beat the RL-200 as the only comparable engine right now is the J-2 which is less efficient and has weird limits on restarts; only the NK-15-V could really replace the RD-254, but the reliability on that is pretty terrible; but for the first stage, the regular NK-15 shows a lot of promise: good thrust, noticeably higher ISP from sea level to vacuum and by setting some of the engines to the non-gimballing version they become noticeably lighter.

The only downside is the poor reliability, but if you're launching a rocket with twenty-seven NK-15s lighting on the pad those data units are going to rack up pretty quickly. I've already looked at converting some existing rockets to use NK-15s and if I do it across the fleet it would get pretty reliable pretty quickly.

With this design, the bottom half of each booster feeds the three engines on the booster while the top half is separated by a decoupler to block crossfeed and has a fuel line to send its fuel to the core stage's eighteen engines. As tested, the top half runs out just before the bottom half so no lugging around spent boosters to suck them dry before ditching them as some of my other rockets do.

This design turned out really well- disturbingly so in fact. Where most other designs I tried for this 3000 ton rocket needed almost 9500m/s to make it to orbit compared to the usual 9000 or so, this one was given close to 9500 but ended up with more than 500 left over in orbit and with a 150 ton payload too.

The main issue...

...is the cost of tooling. Sharing part sizes as much as possible lessens the hit- all the interstage fairings between stages 1-2 and 2-3 are the same diameter and length so are technically "the same" as far as tooling is concerned, while the same 7.5x10m tank is used once on stage 2 and three times on stage 1 and the boosters and third stage tanks are already tooled. A 3000 ton near-Earth avionics costs nearly a hundred grand on its own, but the 7.5m integral tank is close to 300k and is the main reason why I wanted to avoid making new, larger parts for this rocket. There's also the not insignificant cost of buying the NK-15 engine and the first upgraded config for the RD-254, both of which are in the 1969 staged combustion node that just finished researching, how convenient!

Once tooled, it's only fairly expensive and will take close to two months to build. There's a little bit of wiggle room in terms of mass to fit larger fairings when carrying larger payloads (and possibly when that RO or RP-1 change to procedural fairings makes those significantly heavier). With some clever engine grouping it might be possible to do away with the gimbals on all engines and rely on differential throttle as the N-1 was supposed to, but either I deleted that mod or can't find the button for it.

A brief test flight of an NK-15 engined Purple Shape rocket, demonstrating that it could still reach orbit with a 75 ton payload and so was worth the effort of making to gain those data units on the notoriously failure-prone NK-15.

A real launch! Yellow Carillon is a lunar space station, which I only realised after launching hadn't been refitted with vacuum scrubbers and so is stuck with the old lithium hydroxide system instead at least until I send up an extension module.

There were some issues with the second stage tank overheating and exploding despite only having 1 MLI layer on it, fixed by making the pitch rate slightly lower.

Once in orbit, the course was set and the triple RL-10 third stage boosted the station all the way to the Moon. That stage only has near-Earth avionics, but the station's deep space avionics can handle the extra weight of the nearly empty stage so it will also be used to do much of the capture burn in lunar orbit.

A few short burns later to make the orbit fit the lunar space station contract, Yellow Carillon was ready to receive its first crew. That's going to take a while though, so in the meantime the science equipment was switched on and left to run while everything else was powered down.

Spoiler

Full album: https://imgur.com/a/v676yXq

Coming soon: More imaging sat launches and possibly a Gemini mission carrying a scrubber module up to the Yellow Timpani station in LEO. At this point I'm starting to regret training all those new astronauts on Gemini instead of Apollo or the D-2 capsule as I'll probably be moving away from Gemini soon.

[jimmymcgoochie]

Green Mango 2 is first in line for the launch pad.

Unlike the other orbital imaging satellites which will be launched to low-inclination orbits, this one's going polar to cover the entire planet with its SAR scanner, although this will reduce the data gained from the orbital imaging experiment due to the high radiation at the poles (the experiment has an upper limit on radiation above which it doesn't work).

Probably should have noticed that earlier, but as far as the game is concerned the solar panels are working at full power. All four dishes are pointed at the four Green Nectarine relays and data begins streaming back to the ground via the DSN.

This next launch might be Purple Circle Mercury 2? I can't remember exactly what it is, there's only one screenshot but I know that mission was due to launch at around this time so I'm going with that.

Assuming that's the right mission, everything is going OK so far and a course correction is plotted to get a Mercury encounter.

Back to the simulator for a Moon base design. I've worked on this before but now it's finally ready for a full flight test- and I have a rocket that can actually get it to the Moon!

Quad RL-10 Lunex engines will bring it down from lunar orbit to the surface with fuel to spare, though this test landing was a bit rougher than expected...

By this point the engines had done their jobs anyway so losing them doesn't matter. Having those wide fuel tanks also means it's pretty stable even if it touches down with a bit of a sideways drift, though it'll also make fitting it into a fairing that much more difficult.

Test launch using the new Violet Element superheavy rocket. The fairing is larger than anything I've used before at 7.5m diameter, which means much tooling costs (but fairings are weird with their costs so it's actually no more expensive to tool than to build it untooled) and the 40 ton base plus its 60 ton lunar transfer stage are well within this rocket's 150 ton capacity.

This is also the first time I've gone for an RL-200 upper stage over clustered RL-10s, it was simply too heavy to use the smaller engines this time. I looked at the J-2 and it looked like it would get marginally more delta-V (despite being a heavier engine with lower ISP, must be the fuel mix?) but the unlock costs are too high and the weird restart limits are a disincentive too.

I also took a swing at a reusable Moon lander, with mixed results: yes, it has the fuel to land and return and with the advanced lander can too (so two crew), but at almost 20 tons it's nearly double the weight of the existing lander and just not worth it.

Even with a newly unlocked tech node that gave TL4 RCS tech to improve the generic thrusters' ISP, thrust and mass, it'll still take almost 15 tons of propellant per landing as opposed to a 10 ton disposable lander. Unlocking the AJ-10 Transtar with its stupendously long burn time would be great for this, but that's many nodes down the line yet.

A brief check-in on Blue Mandolin Ceres to perform a course correction:

Still no hope of an orbit, but a slow flyby should generate some data and I have an even bigger and more capable-r probe in the works for the next transfer window.

A crewed launch now, with a slight twist: a Yellow Gong D carrying Klaus and Vera up to the Yellow Timpani station in LEO.

This mission is carrying a small module on its nose containing two vacuum scrubbers to take over from the existing lithium hydroxide scrubbers once they run out of lithium hydroxide.

Once docked, I checked to see if any contracts had completed only to realise I'd forgotten to accept any contracts. Sending a crew up to the station gets a decent chunk of funds, an orbital flight contract would have given even more. Ah well, they're up in orbit now and once more astronauts are finished their training I can send another crew up for some extra contract money.

Another Green Mango launch, this time with no additional science experiments to save money and launched to about 30 degrees inclination.

There's another one on the queue and I'm thinking about adding a fifth to make up for the reduced gains from the polar orbit one.

Over to Purple Circle Mercury 2 for a course correction, using up the last of its hydrolox stage in the process. This is slightly concerning as the last Mercury orbit mission needed a good chunk of fuel from that stage to reach orbit along with virtually all the other propellants, but maybe this transfer window is a bit more friendly?

If this doesn't work, the next Mercury mission will be launching on a Violet Element and brute forcing an orbit and maybe even a landing too.

Now for something a bit strange: a derivative of the Green Cucumber but with a huge fairing covering the second stage as well as the payload.

The oversized fairing is required due to the payload- a lunar satellite with a large SAR scanner on it. The heavy SAR array made the whole vessel lopsided, but a combination of sticking everything else on the other side and using the CoM shifter in the avionics has mostly balanced it out.

I've been looking at turning this design into an interplanetary probe to be sent to Venus, Mars, Vesta and Ceres with different configurations- the Venus and Mars probes are identical except for additional solar panels on the Mars version, while the Ceres and Vesta probes will be powered by small nuclear reactors that provide just enough power and are almost exactly as heavy as the SAR scanner so will balance the probes nicely.

Spoiler

Full album: https://imgur.com/a/YCLmEGO

Coming soon: Vesta and Saturn windows are approaching with a launch for each, while crewed lunar operations are set to resume as soon as there's a crew to do so. 

[jimmymcgoochie]

Test simulation of a modified version of the scanning sat shown at the end of the last post, considerably enlarged and refitted to operate around Ceres and Vesta:

The transfer stage has enough delta-V to do the transfer burn, while the probe itself has the delta-V to perform the capture- with a generous margin in case of boiloff and for any course corrections as necessary. I'm not expecting too much boiloff going that far from the Sun, with 50 layers of MLI and active cooling from radiators, but you never know...

Back to "real" missions as the SJ-1 completes another supersonic X-planes contract:

Scatterer settings were a bit messed up, hence the strange wall of light around the horizon. Unfortunately I also messed up the fuel loading and the plane ran out of fuel on the way back to the KSC, forcing a water landing that destroyed the engine.

The pilot was unharmed and the rest of the plane was undamaged, plus there's a jet engine node about to complete on the research queue that unlocks the SR-71 engine that'll give much more speed so it can be refitted right away. It even completed the contract!

Up on the Yellow Timpani station, water is in short supply and liquid hydrogen reserves are also low. Time for Klaus and Vera to come home, sadly contractless as I forgot about that bit.

Back in the bouncy ocean of perpetual energy. The SJ-1 had no such issues, maybe because it was larger and heavier? This might also be a scatterer setting that I've borked and need to fix.

No contracts, barely any retirement delays, barely worth doing. Still, the scrubber module is a long-term investment and there's scope to expand the station if I can resupply it.

A few days in the Spaceplane Hangar later and the SJ-1 is reborn as the SJ-2, featuring a better engine and significantly increased wingspan to reduce the minimum speed and make landing easier. Without having to worry about stability at extreme speeds and altitudes and with the engine able to push the plane right up to 1200m/s before it melts its innards and explodes, moar wing area = less possibility of explosions on takeoff or landing.

A flawless and profitable flight. Not a huge payout mind you, but the plane was cheap enough to build and costs barely anything to operate.

Simulation for a Mercury rover up next. Yes, skipping right past lander to a full-blown rover, which despite its ~300kg mass will require >2900 tons of Violet Element to get it there.

That tiny thing on the very top of the rocket is the rover. It needs three rocket stages on top of the launch rocket just to get out there.

Following the simulated transfer burn, there's still enough left in the tanks to do the capture burn (almost 10km/s!) without using the fuel from the landing stage. Boiloff will be problematic, but much MLI plus radiators should keep it somewhat under control and I've added a little extra hydrogen to compensate.

Purple Cube Saturn 1 is the first mission to use the NK-15 powered Purple Shape rocket, and also the first rocket to use the NK-15 at all. Perhaps unsurprisingly...

Two engines failed on the pad- but since they were symmetrical and the TWR was still good enough the launch went ahead. A third engine failed mid-ascent with a fourth losing thrust near the end of the burn, but despite those setbacks the mission proceeded to orbit without any trouble.

The long transfer burn used the remainder of the second stage's fuel, all of the third stage and a bit of the upper stage to finish, taking almost ten minutes in total.

Despite aiming for a target as large as Saturn, a course correction will still be required to set up a good encounter which should allow multiple flybys of the various moons in future. A second identical probe will be launching in a couple of weeks, right at the peak of the transfer window.

Spoiler

Full album: https://imgur.com/a/RO8gEE0

Coming soon: A launch to Vesta, a launch to Saturn, maybe a launch to the Moon station?

[jimmymcgoochie]

Blue Mandolin Vesta 2 is next to launch, using NK-15 engines on the first stage rather than RD-253s to try and improve their reliability.

Not entirely surprisingly, one engine failed during the ascent:

That didn't stop the launch from proceeding as planned and the probe was duly dispatched towards Vesta where it will orbit, land and potentially have fuel left for some biome hopping.

Purple Cube Saturn 2 launched days later, hitting the peak of the transfer window. The last two launches have somehow gathered the maximum 10,000 data units on the NK-15 so it's now (reasonably) reliable with a 1.6% ignition failure chance.

Another long transfer burn later...

And by aligning the Saturn periapsis with the Titan relative ascending node, an encounter with Titan was set up on the same orbit that will allow the probe to capture into orbit.

Considering Titan's thick atmosphere and low gravity, I might try to land this probe after it gathers all the science from space.

Next to launch is another Green Mango imaging satellite, which was deployed without incident.

Now on to yet more simulations, this time for a Venus rover to fulfil a contract I forgot about. It'll be doing a direct descent from a hyperbolic trajectory, because why not?

The first test started in a highly elliptical Venus orbit just to test the re-entry system:

Good news, it landed almost completely intact despite having no parachutes; bad news, the landing broke an antenna and the heat destroyed the other antenna.

After adding parachutes and swapping to more compact and heat-proof antennae, an all-up test from launchpad to landing. Once again, Green Cucumber GEO provided an extremely reliable launch rocket and the RD-58 (in 11d33m guise) served as the upper stage for the entire transfer burn and any course corrections afterwards.

With an intercept set up that'll get close to Venus (subject to time warp related trajectory shifts...), time for 190 days of time warping with a flagrant disregard for other vessels' nodes, transfer windows and contract deadlines.

A slight nudge to set the periapsis at about 90km and then the upper stage used its remaining fuel to slow down just before atmospheric entry.

One parachute failed when it opened at 5km altitude, but I saved the other one as a backup and it opened at about 500m with no issues to allow a safe soft landing on the surface.

There's no connection to Earth without the relays in orbit, but they'll be launching in the same transfer window so this mission is good to go. Naturally, I'll launch two in case one fails.

The build queue was almost empty a little while ago, but not any more!

Spoiler

Full album: https://imgur.com/a/Et2S49R

  Coming soon: Six of my new astronauts are about to finish Gemini mission training and there are contracts to send crews to both the Yellow Timpani station in LEO and the Yellow Carillon station in lunar orbit, as well as contracts for Earth orbit, lunar orbit, lunar landing, lunar roving...

[jimmymcgoochie]

Two extremely expensive Mercury missions need paying for, maybe I have an active contract to do something?

*checks contracts*

Land on Deimos?

Less than 5m/s of propellant later (including to reorient the craft a few times) and nearly a million funds for it. It was only after landing that I realised Deimos is tidally locked and I've landed on the outward-facing side, limiting communications as this probe can only reach Earth via the Blue Guitar probes in low Mars orbit, but it occasionally gets through (somehow) and after gathering all the surface data I can put it back in orbit to finish that off.

Meanwhile, over at Mercury, Purple Circle Mercury 2 was arriving. A combination of a lighter science payload and potentially a better transfer window means that this probe was easily able to capture into a low polar orbit of Mercury with a decent fuel reserve left over at the end, not literal fumes as with its predecessor.

A valuable contract is completed and all the science instruments are running- hence the elliptical orbit as a couple required >0.04 eccentricity

Violet Hydrogen, the Mercury rover, is already on the build queue, but using basically the same craft but with a different payload should mean I can get terrain and biome maps of the surface too for much contract funds, though the upfront cost will be steep...

The Mercury window coming up soon is a pretty good one, but the following one will cost almost 1km/s more and with a likely rollout time of 12 days per mission I can't launch both of these to Mercury at once. Unless, of course, I build a second unlimited launchpad at a mere 2 million funds, which I currently don't have but can get by completing some crewed lunar contracts.

But before that, Green Okra launches a set of four relays into a high polar orbit of the Earth to try and eliminate communications blackspots for freshly launched rockets in LEO.

The relays were released into a resonant orbit and then circularised on their own, their orbits synced to within 0.001 seconds to ensure they'd stay put for a long time to come.

With those relays in place, the old Green Apple relays (the three low orbit relays seen above) can be decommissioned.

Re-using much of the Green Cucumber GEO's hardware yet again, Green Quince is a station resupply mission to fully top up the tanks on the Yellow Timpani station since it's out of liquid hydrogen, nearly out of water and getting low on food and lox as well.

A relatively straightforward rendezvous and docking ensued within a day of launch and the supplies were transferred over to the station.

I thought about changing the station's orbit with the probe's engine, but it had only one ignition left and I used that to deorbit it instead.

Next to launch was Green Mango 5, the last of the planned imaging satellites. It was positioned and deployed without incident.

And now to the big event- another crewed Moon mission! Newbie astronauts Christa and Marvin are in for an absolute treat for their first flight into space as they're heading to the Yellow Carillon lunar station and then one of them is going to the surface to do some roving.

The launch, using RD-253s because I never bothered to change them to NK-15s they're extremely reliable, had some issues with the second stage spontaneously combusting, but a slightly slower pitch rate solved that second time around. Once in orbit, the trans-lunar burn was started- and then the troubles began. First the upper stage burnt its remaining fuel, but then the stage separation didn't happen properly and the RL-10s on the upper stage didn't light, then only one of them fired up and I had to turn the others off and back on to get them to work, then the node got reset for some reason and I had to complete the burn by eye and then repeatedly correct for the orbital drift knocking the periapsis below the surface.

Once captured, I set up an intercept with the station- and then it hit the ground because timewarp shifted the orbit. Stupid timewarp orbit bug!

Docking was a bit tricky because this vessel was never designed to do so, so in the end the station did the hard work with its much more balanced RCS system. Christa and Marvin made themselves at home as the contracts completed.

Besides these two contracts, there's also crewed lunar orbit, lunar station and crewed lunar landing and rover exploration contracts which this mission should complete. That funding was enough to build the new launchpad, allowing both Mercury missions to leave at the same time and also allowing larger orbital assembly projects in the future.

Spoiler

Full album: https://imgur.com/a/8OjU7oU

Coming soon: Two more newbies go up to the Yellow Timpani station and someone gets their first Moon landing. Besides Mercury, there are transfer windows approaching for Venus and Jupiter as well and a flotilla of missions being built for those opportunities.

[jimmymcgoochie]

Achim and Antony are pretty jealous of fellow newbies Christa and Marvin going all the way to the Moon on their first flight, but they'll just have to live with it and get ready for their own debut mission as they head to the Yellow Timpani space station.

A couple of post-orbital insertion burns later and they arrived at the station within 36 hours. Two contracts paid out just for that, with a third on the cards after they leave the station and move to a higher orbit for a few days.

Meanwhile, over at the Yellow Carillon lunar station, Christa was ready to take the lander down to the surface; this is mildly problematic because the lander is in the middle of the stack, with the Gemini capsule on top and the upper stage booster (that'll take the Gemini back to Earth later) underneath. The upper stage should be controllable, but for some reason (most likely forgetting to add batteries) it wasn't and began floating away in a slow spin after releasing it from the lander, so Marvin was forced to chase after it with the combined Gemini/station and dock with the slowly tumbling booster as Christa watched on.

With their ride home secured (didn't think about that when you were laughing, did you Christa?) it was time for the landing. The crewed landing and rover exploration contract put its landing site just a bit further south than the station's orbit, so a bit of an inclination change was required before landing.

The landing looked good until near the surface, at which point it became clear that it was undershooting a bit. Not great for the future rover driving, but close enough to be drivable by hand. A safe landing in the midlands soon followed.

Spoiler

And one without the benefits of Minimum Ambient Lighting turning the ambient lighting waaaay up:

With the immediate post-landing tasks done, Christa deployed the mini-rover and took it for a spin.

Yup, tiny rover with lots of weight on the top makes it rather unstable. It also turns out to be pretty good at massive lairy drifts when going at speed.

(It's going more or less in the direction of the camera in this shot.)

It took over half an hour to get to the waypoints- should have landed closer- but with that done the contract was nearly complete. There was even time to drive a little ways south to the lowlands to get double the science from this landing.

There were a few incidents during the driving, but nothing too serious...

After "arriving" back at the lander, Christa abandoned parked the rover and got ready to head back to the lunar station. The landing site is still some way south of the station's orbit, but the lander's generous fuel margins mean that's not an issue even after the plane change before the landing.

What is a problem, though, is the solitary docking port currently occupied by the Gemini capsule. With no way to dock, Christa bailed out, grabbed the science and jetpacked her way over to the station- which due to the number of times the rover flipped over had nearly no nitrogen left.

She grabbed the station with 0.1 units left in the tank!

They'll be staying at the station for another thirty days to complete the lunar station contract, plenty of time for Marvin to process all the surface samples as well as the crew experiments on board the station.

Meanwhile, Achim and Antony are done at Yellow Timpani and undock to head to the higher orbit required for the orbital flight contract. 

A successful few days with lots of contracts either completed or just waiting for the crews to return, lots of science gathered and all the interplanetary missions steadily building in the background ready for the upcoming transfer windows. Final scores:

Spoiler

Full album: https://imgur.com/a/6Y0Um6R

Coming soon: Returning these crews to Earth and probably some interplanetary shenanigans.

[jimmymcgoochie]

I've started up a second RP-1 report using Payloads and Launch Complexes, read it here:

P&LC is considerably different to normal RP-1: contracts don't give you funds, KCT points don't exist, the admin building actually does something and reputation is worth something. Suffice to say my first attempt was a total disaster and I ran out of money after less than a year, but second time around things are going better less terribly.

I'll still be focussing mostly on It's Only Rocket Science though.

[jimmymcgoochie]

A short update today, starting with investing the contract money from last time into the VAB to boost build rates.

And now for something completely different: designing the next generation of crewed lunar missions. Gemini has worked well enough up to this point, but only by pushing it far beyond where it was really meant to go: there's nowhere near enough delta-V in the service module to get back to Earth from lunar orbit if something went wrong with the upper stage, re-entry at lunar return velocity is extremely dangerous and deviating even one degree from retrograde will incinerate the capsule (there's a lunar-rated Gemini capsule available, but it's heavier and more expensive than the normal one) and it can only carry a crew of two whereas contracts now are looking for crews of three or more.

The options at present are a) Apollo, or b) D-2. Each has their pros and cons, but I've already used Apollo stuff in Terranism Space Program so I'm going with the D-2 this time around, mostly because it didn't exist back then.

Step 1 was pick an engine to power the CSM, cramming a lot of delta-V into a relatively small and preferably light package without a hideously long burn time. As per usual, the RD-58 was the best all-rounder and with an upgrade to the RD-58M offering a longer burn time and better ISP it was an even more obvious choice. The D-2's RCS is a bit unusual, combining 3-way RCS blocks attached to the service module with built-in RCS on the engine adapter, but the ISP is a mere 260 seconds so is actually worse than Gemini.

Step 2, abort test:

Home-made escape system (sticking some separation motors to the aerodynamic cover) worked exactly as planned and the capsule was yeeted to safety without excessive G-forces.

Step 3: Test it on a lunar round trip. I added the (still heavily WIP) reusable Moon lander design I've been working on, which was about 20kg under the 40-ton weight limit for the avionics I added to the CSM (the built-in avionics can only do 20 tons and I'm already at about 22). Launching on a Violet Element rocket was complete overkill, but it allowed a proper test of the D-2 design including braking into lunar orbit with the lander still attached.

500m/s in lunar orbit with the lander attached turns into 1400m/s without it, plenty to get back home.

If delta-V was going to be a problem, there's always the option of ditching the mission module and just bringing the capsule itself back home, and in fact that might be a good way to add some extra living space to the Yellow Carillon station in lunar orbit.

All in all, a highly successful test. The trick will be getting it to the Moon on a Purple Shape rocket, which is half the weight of the Violet Element and looks to be about 1km/s short of lunar orbit.

Spoiler

Full album: https://imgur.com/a/hrtMkp6

Coming soon: More work on this D-2 design, or designing my own custom service module to use RCS that's actually decent, or possibly trying something completely different with the Apollo capsule instead.

[jimmymcgoochie]

Another short update full of simulations, but instead of those I'll start with this: the first launch of a 3 kiloton Violet Element class rocket.

Violet Hydrogen is a Mercury rover, or at least it should be. It took a mildly ridiculous twenty days to roll this thing out to the pad- no chance of launching this and the Violet Helium planetary scanner to Mercury in the same window without the newly constructed second unlimited launchpad, ULP-2.

A particularly favourable alignment between Earth and Mercury means the transfer burn is under 5km/s and both the departure and arrival points are quite close to the relative AN/DN; the next window is about 1km/s more expensive according to Transfer Window Planner, hence the second launchpad to get both of these missions away at the same time.

The probe was dispatched towards Mercury, with a course correction plotted in about 70 days that should give a nice low periapsis for efficient capture and then landing.

A day later, Violet Helium followed close behind. It might "only" be going to Mercury orbit, but the SAR scanner alone is almost as heavy as the entire Violet Hydrogen rover.

The launch wasn't without issues- PVG had a bit of a funny moment, missing the target orbit and instead veering off course, engine still burning until I manually shut it off. This meant that the transfer burn was a bit more expensive than Violet Hydrogen despite having a slightly more favourable transfer window, but hopefully it'll still make it into a usable orbit for planetary scanning.

A quick stop at Deimos to "launch" the probe landed there back to orbit:

Most of the science was gathered, though the mass spectrometry experiment was only about 20% completed- most likely power issues are to blame. It'll take a few years to transmit all the data back at current rates, so it won't be landing again any time soon unless it's to cheese a contract.

Speaking of cheesing contracts, I took one to land on an asteroid for one important reason: there's an asteroid already in Earth orbit, presumably captured thanks to a lunar assist. I spotted it a few weeks ago and at some point in the future I'll throw a probe at it, though hopefully RSS asteroids aren't almost as large, or even larger, than physics range like they were before...

Spoiler

Zoom in close in the very centre of the image, that tiny white speck is a probe! The second time I tried this, the asteroid was larger than physics range so the probe was instantly destroyed after the asteroid spawned in.

Lots of sims now: first I looked into building custom service modules for both the Apollo and D-2 capsules, with somewhat mixed results...

(This worked perfectly well, but used quite a bit of the service module's fuel to make it to orbit which isn't ideal.)

In both cases the booster was nicked from the Green Cucumber GEO with minor tweaks; with a failure rate of less than 0.01% on the RD-107 and RD-108 it's not hard to see why. I even looked at just copying the Yellow Croissant from Terranism Space Program with the original Apollo capsule rather than the five-seater Block 3, but that would take too much tooling for right now.

Then I got distracted by the blurb for an NK-15 upgrade that mentioned the Soyuz 2.1v which swaps the RD-108 core for an NK-33. Initially I looked at doing the same on the Green Cucumber GEO, but by the time I was done looking at all the different fuel ratios for the NK-9/9V/15/15V variations I had something totally different:

It worked pretty well- this particular combination of configs use the same fuel mix so the boosters can feed fuel to the core- and allowed the second stage of the existing design to be dropped entirely, but then I remembered that vacuum-optimised engines have huge ignition chance penalties at high pressures and the NK-9V simply wouldn't work at sea level, so I tried a boosters-and-airlit-core design instead:

Which worked OK, until I turned on part failures and had the same booster engine fail four or five times in a row on successive simulations. Powerful and efficient they may be, but these NK engines aren't all that reliable especially compared to the RD-107/108 they're supposed to be replacing.

After that, I switched to a more conventional (and sensible!) stage arrangement rather than the rather silly boosters-and-airlit-core thing and managed to make it even smaller and lighter at just over 200 tons, not to mention considerably cheaper.

The second stage burn time of almost 10 minutes did result in some serious efficiency losses in the test, requiring about 500m/s from the upper stage to make it to orbit and meaning that it arrived in GEO by the skin of its teeth:

Some additional work is required to make this truly viable, but once those wrinkles are ironed out this could be a much more cost-effective way of doing those satellite contracts and potentially opens the door to upping the payload requirements to get even more money per launch.

Spoiler

Full album: https://imgur.com/a/tjUO0hm

Coming soon: Venus and Jupiter transfer windows are approaching with multiple missions due to launch to both planets and a mere three days between the optimal launch windows.

[jimmymcgoochie]

Many launches to come today! First up is the first Green Amethyst GEO contract sat, replacing the old Green Cucumber with more than double the payload capacity-

I should have known reliability would be a problem- the upgraded NK-33 config starts out at about 93% ignition chance, compared to >99.99% chance for the RD-107/108, though it will improve in time. The rocket was rolled back, engine replaced and rolled out for a second attempt.

Meanwhile, I came up with an idea- use the first stage of this rocket, with some minor tweaks, to launch a Gemini capsule into orbit. It turned into an SSTO for some reason and things didn't go too well...

Excessive G-forces at the end of the burn (over 10G despite throttling the engines down to minimum thrust), plus the fact that it's heavier and more expensive than the existing launch rocket and the upcoming move away from Gemini to D-2, means this is one design I won't be taking forward.

Back to the Green Amethyst for the second launch attempt:

A significant increase in contract value- at least 30k funds- for a mere 2000 more funds to build the rocket? That's a win in my book.

Now on to the interplanetary missions! Venus and Jupiter windows are both open so there's a lot of them.

Green Radish 1, Venus rover:

Its identical twin rover will be launching in about a month to see if the more favourable "flyby" window is better or worse than the "orbit" window.

Purple Cube Jupiter 1:

Should have ample fuel to capture into Jupiter orbit and do repeated flybys of the Galilean moons, with the potential to try and orbit one of them if the opportunity arises.

Purple Cube Jupiter 2:

Also sent on its way without incident.

Spoiler

Well, unless you count this:

There's a probe on the build queue to complete this contract so I won't take this contract again until I actually succeed the first time. A free million funds for a glitch is a bit too far, even for me.

Purple Sphere Venus 1:

Back down to Earth (sort of) for another Yellow Gong LEO Gemini mission, carrying Pat and Tony for what might be their first missions. It's the first time I've launched two engineers on the same mission, but that's mostly because everyone else is doing training right now, either for the D-2 or X-15.

A quick visit to the Yellow Timpani space station...

And a few days at higher altitude, during which I noticed that the fuel cells weren't producing enough power to run all the systems for some reason:

And then back home with some scatterer-related weirdness (strange sky colours, bouncy ocean) because CKAN decided I needed to reinstall every single mod because CKAN itself had done an update.

Looking back, I think Antony had a flight before which would explain the reduced retirement delay compared to Patricia who definitely hasn't.

Green Satsuma 1, asteroid chaser:

Following a course correction a few days later, the closest approach is down to a few kilometres- but critically outside of physics range. RSS asteroids are stupidly large and can sometimes be larger than physics range but this one seems to be approachable; still, best to do so slowly rather than crashing into the multi-gigaton space potato.

I took a look at what other transfer windows were coming up and found a Neptune window that's just about usable if I build a probe RIGHT NOW. Ironic, since the journey will take over thirty-four years and so would last until mid-2003.

I'll probably send a later mission with much more delta-V and arrive before this one and I'm not sure this probe would actually be able to capture into a useful orbit, so I might not go ahead with this one.

That Neptune probe also uses a new launch rocket design, broadly similar to the Purple Shape but with a single 7.5m diameter first stage core instead of the Proton-style design with 3m side tanks and a 5m core. It's a bit heavier, but can carry an enlarged second stage giving greater total delta-V. Working title is Purple Geometry and the probe has been named Purple Tangent.

I also designed a new Moon rover which should be better equipped to handle those long lunar nights, since the old Green Huckleberry rovers seem to be perpetually low on power and still have a lot of science (mostly mass spectrometry 4) to do. Using the new 350t launch vehicle I designed for the new GEO sat launcher so these rovers are named Green Basalt.

Spoiler

Full album: https://imgur.com/a/kIE5kfZ

Coming soon: A few rover launches and "landing" on an asteroid.

[jimmymcgoochie]

Whoops, I forgot to post two whole Imgur albums' worth of stuff... Still, better late than never!

A design-heavy update first as I experimented with a modular lunar space station that would host reusable landers as well as the fuel tankers required to run them and crews to use them.

Getting all this stuff out to the Moon won't be easy- or cheap!- but it'll provide an ideal way to explore the Moon or visit a surface base.

And now for a reusable spaceplane to serve as an upper stage for launching small payloads. As a plane, it was...

...surprisingly successful, actually, with decent stability, a reasonable landing speed and no explosions during testing.

Trying to put the "space" part of "spaceplane" into it proved rather less successful:

Despite what the part descriptions might say, those shielded fuel tanks were completely unable to take the heat of re-entry and even the most heatproof RCS stood no chance.

How about a reusable first stage then?

That didn't work either, and most of the tests I did went resulted in the entire booster being destroyed on splashdown.

Enough simulating, time for a real launch instead! Green Basalt 1 is the first next-generation rover heading to the Moon, with others due to head out there in due course.

While that was heading to the Moon, course corrections came up for the Violet Hydrogen and Violet Helium missions to Mercury, which are still on track to reach their goals.

Meanwhile, Green Satsuma approached the magic disappearing rock.

Keep an eye on that tiny white speck just off the end of the upper left solar panel, just above the Earth.

Now spot the tiny white speck near the bottom of the asteroid- that's the probe!

Asteroid "landing" successful, though I wonder just how big an avionics unit I'd need to make almost 3 gigatons of asteroid controllable... This contract glitched and paid out a while ago, hence no contract reward now.

Now the launch of Green Radish 2 to Venus, which waited for a "more efficient" window that TWP insisted was coming (it lied).

One last sim, this time a tiny lightweight D-2 capsule with no mission module for absolute cheapness in LEO operations.

This actually worked rather well.

And after all that, Green Basalt 1 arrived at the Moon and parked in orbit until the near side was in daylight for its landing.

Spoiler

Full album: https://imgur.com/a/Ba0898c

Coming soon: a hiatus of a few weeks, as I'll be KSP-less until 2023.

[jimmymcgoochie]

I'm baaack!

Which naturally means I have to try and figure out what I was doing two weeks ago.

A simulated launch of the new lunar station core module went well enough to build it. During the tests I experimented with an even larger version of the Violet Element rocket with four boosters and a launch mass of 4000 tons (a 33% increase in mass and booster count) but the meagre delta-V gains weren't worth the additional tooling cost required to build it- for now.

I also worked on some lunar tanker designs to carry the necessary fuel out to the Moon for the reusable Moon lander. In order to avoid engine ignition limits (and failures) the lander uses generic thrusters which aren't particularly efficient, so the fuel required for one landing is heavier than sending a new single-use lander and the tankers are correspondingly large.

This is the 'light' version carrying enough fuel for a single landing and able to get itself to the station once thrown in the general vicinity of the Moon. Reusing existing toolings means this is a pretty cheap option, which also explains the weird blister tanks on the sides which contain food supplies for the crews out at the station. Those are 3m diameter tanks.

A considerably larger tanker with 5m diameter tanks, carrying almost triple the fuel. It'll take some tooling, but only costs about 50% more than the smaller tanker despite packing more than double the fuel, though the rocket required to get this heading Moonwards will be considerably larger and more expensive too.

Lander for reference.

And to finish off the simulations, the new Moon "base" which by this point is a D-2 capsule and mission module with some extra food and some landing legs stuck to it. Cutting the weight of the lander led to savings elsewhere and means it can launch on a 1500 ton Purple Geometry rocket instead of the larger and more expensive Violet Element.

There was also a cursed geostationary contract sat as MechJeb stubbornly refused to accept that the descending node existed, preferring to put the GTO burn at a random spot about 10 minutes before the ascending node (which funnily enough worked fine if I told MechJeb to put the node there) until I eventually just plotted the burn at the AN and moved it around myself until it was at the right place.

Spoiler

Full album: https://imgur.com/a/EsiiWPl

Coming soon: I need to do a sit-rep on all the active and planned missions to refresh my memory, so probably a very image-heavy but progress-light post.

[jimmymcgoochie]

Back by popular demand, it's Name That Speck!

It's... *drumroll*

Ceres! And since this is the probe with the transfer stage that failed, a flyby is all that it'll get. Better luck next time I hope.

Meanwhile, Green Basalt 1 touched down on the Moon mostly as planned:

The engine exploded a bit, but the rover itself is unscathed and can begin its science mission. Lessons learnt from this one will go into improving the two others awaiting their own launches.

After a launch that wasn't screenshotted because I forgot, Purple Tangent Neptune was dispatched on its 30-something year trip to the outermost planet.

It's 1969 now so this probe will be arriving in the new millennium. 

Spoiler

I've gone through the Tracking Station to tidy up some old/dead vessels and to see what active missions I have and where they're going. Full album with details: https://imgur.com/a/D7GRL4C

Coming soon: Rockets and stuff? I've barely looked at this save this month so I really can't remember.

[jimmymcgoochie]

Wow, it's been that long since I played this save? There's only one save file from this year!

Coming back to an old save after a long hiatus can have some unexpected side effects, as you'll see later, but for now I'll start with the launch of the second Green Basalt lunar rover. It was only after I'd launched this that I remembered I was going to keep it for a while so I could test out the first one for a while, but that's what I get for not really playing this save this year.

It's nice to be back in a save where I can just launch something to the Moon in a few easy clicks instead of spending the whole time penny-pinching as seems to be the norm in P&LC. This mission overlapped with the arrival of two much bigger ones, however by pure coincidence the timings didn't clash at all and I could focus on Mercury.

First up, Violet Hydrogen arrived at the innermost planet and captured into orbit, eventually.

A million funds, just like that. I've missed this...

But this mission isn't just stopping in orbit!

It turns out I'd underestimated the delta-V required to land on Mercury and even with the dregs of the capture stage chipping in I still only landed thanks to past me planning for this eventuality with a very powerful decoupler under the rover and some emergency RCS to allow it to land itself.

Parallax really doesn't like Mercury, it looks ugly at a distance and got really glitchy up close; those black areas are texture glitches and they were flickering like crazy whenever I moved the camera even slightly. Science is a-gathering but without a signal to Earth it'll be a while before it can be sent home or the Bon Voyage autopilot activated to drive the 4200km or so to the waypoints for the Mercury rover contract. Yes, I landed on the wrong side of the planet; no, it wouldn't have been all that much better no matter how long I waited, the orbit I ended up with was nowhere near the waypoints.

Barely a day later, Violet Helium arrived and did its capture burn with equal success. Both missions had some hydrogen boiloff but a combination of small bonus tanks of hydrogen and pumping from the lowest stage to top up the other tanks and then dumping lox to reach the right ratio meant they weren't impacted, and I'd budgeted extra fuel for that reason.

After a brief panic when the capture burn left it suborbital and heading for the surface, the probe recovered and parked in a ~495km circular polar orbit and deployed its science and scanning equipment. The big SAR scanner wants a much higher altitude but space low science and the radar altimeter scanner are happy where they are.

A quick jump over to the KSC to fly the SJ-2 supersonic plane for an easy contract, where the various mod updates that have come in since the last time I played this save nearly cost me a plane: the cockpit now has an ejector seat that's automatically set to the abort action group, but I use abort to toggle the airbrakes on my planes and nearly yeeted the poor pilot out of his plane while approaching the KSC; fortunately for me the ejector seat only works at subsonic speeds and it was going too fast to actually deploy, giving me time to change the action groups.

This addition does mean I can get rid of the cockpit ejection system and the solid rockets that are currently making these contracts not complete because "It HaS rOcKeTs", so I've been alt+F12-ing them complete up until now.

Back to the Green Basalt 2 which finally arrived at the Moon and landed on the far side via the usual "land on the engine and crush it" technique.

The rover was stuck for a while until I remembered it had RCS thrusters underneath to make it "fly" and dislodged it from its perch.

And now for the part where all those updates finally caught up to me. I'd rolled out a Yellow Gong F for a nice easy Gemini mission a few months ago and just launched it today without checking if anything was wrong, because why would anything have changed?

Uh...

That's not good...

And once again ejector seats nearly killed my Kerbals- they didn't have their own parachutes!- but once again it was going too fast to trigger it.

The engine models have obviously been changed in the last few months, something I now remember seeing when porting rockets over from this save to Get With The Program but which I forgot about coming back here. The engines still worked perfectly well despite being recessed a few metres into the tanks but the verniers didn't have nearly enough leverage to control the rocket's pitch, so it just kept pitching over and ended up pointing downwards and causing the launch abort.

The crew are unharmed but lost their mission training. I could build another one and fix the engine issue, but with the first LEO D-2 almost ready and most of my astronauts training for that I'm not sure if it's worth it. I'll double check the contracts to see if they'll time out before the D-2 is ready to launch.

Spoiler

Full album: https://imgur.com/a/HlD4Qgu

Next time: Launching a lunar space station?

[jimmymcgoochie]

Spoiler

Very funny, Waterfall, very funny...

With the future lunar station core ready to go, it's about time I figure out how to get the rest of the station's modules out there. The propulsion and habitation modules together are about the same size and weight as the core module and so the same (huge) rocket can be used to get them there, with a generous margin:

The lab module is a bit heavier than the hab module but significantly lighter than the propulsion module and can be sent on its own on a smaller rocket.

Considerable science is being returned from Mercury as the Violet Hydrogen and Helium return data from the innermost planet. (Ignore the buildings under the ground, they're just glitchy sometimes)

The transfer window to Mars is open, so cue the launch montage!

A rare event- interplanetary transfer burn actually aiming right at the target planet.

And now for the big one:

With those probes on the way, a quick stopover at the Saturn-bound mission to perform a course correction.

Note to self: accept the Enceladus flyby contract once the Saturn flyby contract is completed.

And then it's onwards to the crewed lunar infrastructure launches, starting with a crew rover to take crew to and from the upcoming surface base.

Lots of fuel left in the thrusters is good, however due to a bad capture burn putting it on a suborbital trajectory it ended up on the wrong side of the Moon and will have a loooong drive ahead of it to get over to the base.

It seems Violet Hydrogen finally got enough data back to complete the Mercury landing contract and earns a BIG payday.

Now for something a little different and a little, well, little.

The second asteroid landing contract says nothing about it being a different asteroid, so this tiny probe is going after the same asteroid as the first one, sitting in a polar and very elliptical Earth orbit.

The Moon base mission started as it was to continue with a staging error on the clamps resulting in it clipping the topmost clamp with the bottom of the rocket, almost tipping over.

It recovered from this and continued on its way.

It was going quite well until I remembered that the J-2 only has three ignitions and I'd already used two to get to a relatively high lunar orbit. The J-2S is throttleable to a fairly low minimum which helped control the rate of descent before the LMDE took over for the last few kilometres to the surface, but it wasn't an easy descent. Things got worse as the base touched down with some lateral velocity and began tipping over, forcing it to lift off, correct the resulting horizontal velocity while hovering over the surface and then set itself down again. No screenshots of this because I was too busy frantically trying to avoid losing the entire mission.

Is it a base? Is it a D-2 capsule and mission module with some extra greebles and gubbins stuck to the sides? Is "both" an acceptable answer?

Final scores:

Spoiler

Full album: https://imgur.com/a/ku9U3ym

Next time: Completing that Gemini mission that failed last time due to the engine models being changed, then more lunar infrastructure launches.